German Silver 3 Ducat "Medallic Coinage. Argenteus Issues" 1960 X# M99

Obverse
Value in center of 6-pointed cross, lilies in angles
Lettering: III PRO PROSPERITATE MUNDI 1000 ARGENTEUS

Reverse
Athenian owl above helmeted head of Minerva left
Lettering: GRAECIA ANNO A.CHR.N.CDXC PUGNA MARATHONIA VICIMUS 490 A.CHR 1960